Methods for melting reactive glasses and glass-ceramics and melting apparatus for the same

ABSTRACT

A method of melting glass and glass-ceramics that includes the steps: conveying a batch of raw materials into a submerged combustion melting apparatus, the melting apparatus having liquid-cooled walls and a floor; directing a flame into the batch of raw materials and the melted batch with sufficient energy to form the raw materials into the melted batch; and heating a delivery orifice assembly in the floor of the submerged melting apparatus to convey the melted batch through the orifice assembly into a containment vessel. The melted batch has a glass or glass-ceramic composition that is substantially reactive to a refractory material comprising one or more of silica, zirconia, alumina, platinum and platinum alloys.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.16/321,898 filed on Jan. 30, 2019, which was the national stageapplication under 35 U.S.C. § 371 of International Application No.PCT/US2017/044833, filed on Aug. 1, 2017, which claims the benefit ofpriority to 35 U.S.C. § 119 of U.S. Provisional Application Ser. No.62/370013 filed on Aug. 2, 2016, the contents of which are relied uponand incorporated herein by reference in their entirety.

BACKGROUND

The present disclosure relates generally to methods for melting glassesand glass-ceramics and melting apparatus for the same and, moreparticularly, to methods for melting reactive glasses and glass-ceramicsand submerged combustion melting (“SCM”) apparatus and delivery orificeassemblies for the same.

Many reactive glass and glass-ceramic compositions present significantchallenges in developing melting processes suitable for use on amanufacturing scale. Although these compositions can degrade refractoryand precious metal furnace linings, they often can be meltedsuccessfully in the laboratory or at a pilot scale. With smaller volumesof materials, it is possible to limit the exposure time of thesecompositions with furnace linings susceptible to corrosion when meltingis conducted in the laboratory or at a pilot scale. Moreover, therelatively smaller size of the melting apparatus employed in thelaboratory and at a pilot scale can make single-use furnace liningsfeasible from a cost standpoint when melting reactive glasses andglass-ceramics.

As the processing of reactive glass and glass-ceramic compositions isscaled to batches and volumes suitable for manufacturing, corrosion anddegradation of furnace linings becomes a serious problem. Put simply,certain glass and glass-ceramic compositions will corrode and destroyfurnace linings during melting and fining operations, particularly asexposure times at temperature must be increased to ensure homogeneity ofthe melt. For example, high copper-containing antimicrobial glasscompositions are reactive with both refractory (e.g., materialsconsisting essentially of silica, zirconia, alumina and combinationsthereof) and precious metal furnace lining materials. While highcopper-containing antimicrobial glass can be melted successfully in thelaboratory, manufacturing of this glass is cost-prohibitive asconventional melting approaches and apparatus cannot be employed to meltat high volumes.

Accordingly, there is a need for methods of melting reactive glasses andglass-ceramics, along with melting apparatus for the same, suitable forscaling to volumes suitable for manufacturing. There is also a need formethods and melting apparatus that minimize degradation and corrosion tofurnace components in contact with reactive glasses and glass-ceramicsduring processing.

SUMMARY

An aspect of the disclosure pertains to a method of melting glass andglass-ceramics that includes the steps: conveying a batch of rawmaterials into a submerged combustion melting apparatus, the meltingapparatus having liquid-cooled walls and a floor; directing a flame intothe batch of raw materials and the melted batch with sufficient energyto form the raw materials into the melted batch; and heating a deliveryorifice assembly within the floor of the submerged melting apparatus toconvey the melted batch through the orifice assembly into a containmentvessel. Further, the melted batch has a glass or glass-ceramiccomposition that is substantially reactive to a refractory materialcomprising one or more of silica, zirconia, alumina, platinum andplatinum alloys.

In some embodiments of the method, the melted batch includes a skulllayer in contact with the walls and the bottom of the submergedcombustion melting apparatus. The skull layer developed during themethod also can range in thickness from about 0.1 to about 5 inches inthickness.

In other embodiments of the method, the conveying, directing and heatingsteps are further controlled such that the melted batch is continuouslyconveyed or periodically conveyed into the containment vessel. Themelted batch can be continuously conveyed into the containment vesselthrough a delivery orifice assembly by the heating step. Preferably, theorifice assembly is lined with a tin oxide liner element. It is alsopreferable to conduct the step of heating the delivery orifice with aninduction heating process.

In another aspect, the conveying step can be conducted such that thebatch of raw materials is conveyed below a glass line of the meltedbatch. In other aspects, the conveying step can be conducted such thatthe batch of raw materials is conveyed above a glass line of the meltedbatch.

In further embodiments of the method, the glass or glass-ceramiccomposition includes copper in the form of a copper-containing oxide.For example, the glass or glass-ceramic composition can be anantimicrobial glass composition comprising a copper-containing oxidethat ranges from about 10 to about 50 mol %.

In an additional aspect of the method, the step of directing a flameinto the batch of raw materials and the melted batch can be conductedwith sufficient energy to agitate the melted batch such that the meltedbatch in the containment vessel is substantially homogeneous. The stepof directing a flame can also be conducted according to a ratio ofoxygen to fuel that is set based at least in part on an oxidation stateof at least one metal (e.g., copper) in the glass or glass-ceramiccomposition. Further, the fuel employed in the step of directing a flamecan be natural gas and the ratio of oxygen to natural gas can be setfrom about 2:1 to about 3:1.

Another aspect of the disclosure pertains to a delivery orifice assemblyfor a submerged combustion melting apparatus that includes: a susceptorsleeve comprising a sleeve end for coupling to a submerged meltingapparatus; a coil surrounding the susceptor sleeve that is configured asan inductor and a liquid coolant conveyance; and an inner liner having afirst refractory composition that is configured within the sleeve, theinner liner further configured to convey a melted batch from the meltingapparatus and comprising a liner end in proximity to, or in contactwith, the sleeve end. The melted batch has a glass or glass-ceramiccomposition. The delivery orifice assembly also includes a top cappositioned over the sleeve end and the liner end, the cap having thefirst refractory composition and configured for contact with the meltedbatch in the melting apparatus, and the cap further comprising anorifice substantially coincident with the liner end. The deliveryorifice assembly further includes an induction heating controllercoupled to the coil for inductively heating the susceptor to controlflow of the melted batch through the orifice and the inner liner.

In an embodiment of the delivery orifice assembly, the glass orglass-ceramic composition is substantially reactive to a refractorymaterial comprising one or more of silica, zirconia, alumina, platinumand platinum alloys. The glass or glass-ceramic composition can includecopper in the form of a copper-containing oxide. For example, the glassor glass-ceramic composition can be an antimicrobial glass compositioncomprising a copper-containing oxide that ranges from about 10 to about50 mol %.

In a further embodiment of the delivery orifice assembly, the firstrefractory composition can be selected from refractories consisting ofquartz, tin oxide, chrome oxide, alumina, fused zirconia, zirconia,zirconia-silica, and combinations of these refractories. In a preferredaspect, the first refractory composition comprises tin oxide.

Another embodiment of the delivery orifice assembly is configured suchthat the susceptor sleeve has a composition selected from the groupconsisting of a steel, a precious metal and a precious metal alloy.Further, the susceptor sleeve can include an inner flange, configuredsuch that the inner liner rests on this inner flange.

A further aspect of the disclosure pertains to a submerged combustionmelting apparatus that includes: a melting vessel for preparing a meltedbatch, the vessel comprising a plurality of walls and a floor, eachcomprising a metal alloy and a water-cooling element; a port in one ofthe walls for conveying a batch of raw materials into the melted batch;a burner in the floor for directing a flame into the vessel withsufficient energy to form the melted batch; and a delivery orificeassembly in the floor for delivering the melted batch into a containmentvessel. Further, the melted batch has a glass or glass-ceramiccomposition that is substantially reactive to a refractory materialcomprising one or more of silica, zirconia, alumina, platinum andplatinum alloys.

In the aspect of the disclosure that pertains to a submerged combustionmelting apparatus, the delivery orifice assembly can be configuredaccording to any of the aspects of the delivery orifice assembliesoutlined in the foregoing or consistent with the principles that animatethem. For example, the first refractory composition can be selected fromrefractories consisting of quartz, tin oxide, chrome oxide, alumina,fused zirconia, zirconia, zirconia-silica, and combinations of theserefractories. Further, the susceptor sleeve can have a compositionselected from the group consisting of a steel, a precious metal and aprecious metal alloy. The susceptor sleeve may also include an innerflange, configured such that the inner liner rests on this inner flange.

In another embodiment of the submerged combustion melting apparatus, theport is located at a position in one of the walls for conveying thebatch of raw materials below a glass line of the melted batch. In otheraspects, the port can be located at a position in one of the walls forconveying the batch of raw materials into the melted batch above itsglass line.

Additional features and advantages will be set forth in the detaileddescription which follows, and will be readily apparent to those skilledin the art from that description or recognized by practicing theembodiments as described herein, including the detailed descriptionwhich follows, the claims, as well as the appended drawings.

It is to be understood that both the foregoing general description andthe following detailed description are merely exemplary, and areintended to provide an overview or framework to understanding the natureand character of the claims. The accompanying drawings are included toprovide a further understanding, and are incorporated in and constitutea part of this specification. The drawings illustrate one or moreembodiment(s), and together with the description serve to explainprinciples and operation of the various embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic, cross-sectional view of a submerged combustionmelting apparatus according to an aspect of the disclosure.

FIG. 1A is a cross-sectional, optical micrograph of a wall of asubmerged combustion melting apparatus after a method of melting aphase-separable, copper-containing glass according to an aspect of thedisclosure.

FIG. 2 is a schematic flow chart of a method of melting glass andglass-ceramics according to an aspect of the disclosure.

FIG. 3A is an exploded, schematic view of a delivery orifice subassemblyaccording to an aspect of the disclosure.

FIG. 3B is a cross-sectional, schematic view of the delivery orificesubassembly depicted in FIG. 3A.

FIG. 3C is a cross-sectional, schematic view of a delivery orificeassembly that includes the delivery orifice subassembly depicted in FIG.3A.

FIG. 4 is a schematic, plan view of a submerged combustion meltingapparatus with multiple burners and delivery orifice assembliesaccording to an aspect of the disclosure.

DETAILED DESCRIPTION

Reference will now be made in detail to various embodiment(s), examplesof which are illustrated in the accompanying drawings.

Aspects of the disclosure generally pertain to methods of and apparatusfor making copper-containing antimicrobial glass that include secondphase particles comprising glass compositions with antimicrobialproperties. The antimicrobial properties of the glasses disclosed hereininclude antiviral and/or antibacterial properties. As used herein, theterm “antimicrobial” means a material, or a surface of a material, thatwill kill or inhibit the growth of bacteria, viruses and/or fungi. Theterm as used herein does not mean the material or the surface of thematerial will kill or inhibit the growth of all species of microbeswithin such families, but that it will kill or inhibit the growth of oneor more species of microbes from such families.

As used herein, the term “log reduction” means—log (C_(a)/C₀), whereC_(a)=the colony form unit (CFU) number of the antimicrobial surface andC₀=the colony form unit (CFU) of the control surface that is not anantimicrobial surface. As an example, a “3 log” reduction equals about99.9% of the bacteria, viruses and/or fungi killed. Similarly, a “5 log”reduction equals about 99.999% of bacteria, viruses and/or fungi killed.

Aspects of the disclosure generally pertain to methods of and apparatusfor making glass and glass-ceramic compositions that are reactive tofurnace linings and other furnace components comprising refractorymaterials. As used herein, “a glass or glass-ceramic composition that issubstantially reactive to a refractory material” includes glass andglass-ceramic compositions that render, through corrosion, reaction,degradation or other contact, a conventional refractory materialunusable after completion of one or more batch melting runs or periodicmelting run time which totals an amount that is less than sufficient forcost-effective manufacturing of the glass and glass-ceramiccompositions. Conventional refractory materials include, but are notlimited to, refractory materials that include one or more of silica,zirconia, alumina, and precious metals that include one or more ofplatinum and platinum alloys.

Preferred glass or glass-ceramic compositions that are substantiallyreactive to a refractory material and suitable for melting according tothe methods and/or with the melting apparatus of the disclosure includecopper-containing, phase-separable antimicrobial glass compositions(“Cu-containing AM glass”). These Cu-containing AM glass compositionsinclude those disclosed in U.S. Patent Application Publication No.2015/0230476 (“US '476”), published on Aug. 20, 2015, the salientportions of which that are related to these compositions are herebyincorporated by reference in this disclosure in their entirety.Typically, the Cu-containing AM glass compositions in US '476 are highin copper content, preferably containing copper-oxide in the range fromabout 10 to about 50 mol % and silica in the range from about 40 toabout 70 mol %. These compositions also typically contain a cupritephase and a glass phase. Certain embodiments include a plurality ofcopper ions, a degradable phase including B₂O₃, P₂O₅ and K₂O, and adurable phase including SiO₂.

The glass and glass-ceramic compositions of the disclosure that aresubstantially reactive to a refractory material can degrade suchmaterials according to at least two mechanisms. First, for refractorymaterials that are classified as refractory ceramics (e.g., silica,zirconia, alumina and combinations thereof), these materials can bedissolved by glass compositions that are very fluid at meltingtemperatures and possess a large amount of fluxes and/or low temperatureglass formers (e.g., B₂O₃ and P₂O₅) compared to higher temperature glassformers (e.g., SiO₂ and Al₂O₃). Glass compositions with high amounts ofalkali metals, alkaline earth metals, boron, phosphates, halides andmetal oxides compared to silica and alumina often are substantiallyreactive to ceramic refractories (but perhaps not reactive to preciousmetal, refractory materials). That is, if a glass is ‘starved’ of silicaand alumina by having larger quantities of low temperature glass formersand/or fluxes, the glass will tend to pull it from any refractory comingin contact with it.

For example, the Cu-containing AM glass compositions typically containabout 20 to 40% copper oxide in order to obtain antimicrobial behavior,including bacterial, viral and/or fungi kill levels commensurate withlog reduction levels of “3 log” or more. As these glasses typically havesilica levels below 70 mol %, they are substantially reactive withconventional refractory materials. Other substantially reactive glassesinclude high refractive index ophthalmic glasses. To achieve highrefractive indices in these glasses, heavy metal elements areincorporated into the glass matrix such as barium, lead, lanthanum,germanium and niobium. Additional alkali metals and alkaline earthmetals are added to ensure that such glasses will melt at reasonabletemperatures, ensuring that these glasses have relatively low silicalevels, typically about 40% by weight or less.

On the other hand, most commercially available glass compositions withsilica concentrations of around 70 wt. % or more are not substantiallyreactive to conventional refractory materials classified as refractoryceramics. For example, soda-lime glass typically includes about 70%silica by weight, 15% sodium oxide and 9% calcium oxide and is notsubstantially reactive to conventional refractory materials. Similarly,Corning® Pyrex® glass has a silica content of about 81% by weight, alongwith boron oxide at 13.2% by weight, alumina at 2.3% by weight and isalso not substantially reactive to conventional refractory materials.

Second, for refractory materials that are classified as precious metals(e.g., platinum, platinum alloys, gold and others), the corrosionmechanism for the substantially reactive glass and glass-ceramiccompositions of the disclosure involves the reduction of multivalentions (e.g., Fe, Cr, Mn, Cu, Sn, Sb, As, Se, and Ag) within the glass orglass-ceramic composition that can alloy with the precious metal andlower its melting point. If the melting point of the precious metal isreduced to a temperature that is below the temperature of the meltedbatch of the glass or glass-ceramic composition in a melting apparatus,the precious metal will decompose and end up mixed within the meltedbatch of the glass or glass-ceramic composition. When the multivalentions are at relatively low levels of about 1 weight percent or less,they may alloy with the precious metal refractory materials (e.g., afurnace lining) and melt within the structure having the precious metalrefractory material with little to no negative impact. On the otherhand, when the multivalent ions are included at higher levels of morethan 1 weight percent within a glass or glass-ceramic composition, thesecompositions are substantially reactive—i.e., they can alloy with theprecious metal refractory material and easily destroy the structurefabricated from the precious metal refractory material (e.g., a furnacelining).

For example, Cu-containing AM glass compositions with copper levels farexceeding 1 weight percent are substantially reactive to preciousmetal-containing refractory materials. When melted in contact withprecious metal-containing refractory materials (e.g., furnace linings),the Cu-containing AM glass compositions can alloy with the preciousmetals and significantly lower their melting point leading todegradation and corrosion of structure fabricated from the preciousmetals during melting of these glasses for purposes of processing andmanufacturing. As another example, high antimony glasses employed infiber amplifier applications typically contain antimony levels of about20 weight percent. As such, if the antimony in the glass is reduced, itis likely to alloy with any refractory materials containing preciousmetals, leading to premature destruction of the structure containing theprecious metals in contact with the glass during processing.

Referring to FIG. 1, a submerged combustion melting apparatus 100 isdepicted according to an aspect of the disclosure. The SCM apparatus 100includes a melting vessel 10 for preparing a melted batch 20, which hasa glass or glass-ceramic composition that is substantially reactive to aconventional refractory material. In some aspects, the conventionalrefractory material can comprise one or more of silica, zirconia,alumina, platinum and platinum alloys. The melting vessel 10 of the SCMapparatus 100 can take on a variety of shapes, sufficient foraccommodating various volumes of melted batch 20. As depicted in FIG. 1,the vessel 10 is fabricated in a rectangular cuboid shape with four (4)planar-shaped walls 12 and a floor 14. Other suitable forms for vessel10 include cylindrical shapes with one (1) wall 12, various cuboidshapes, typically with four (4) planar-shaped walls, and othervariations of these shapes.

The walls 12 and floor 14 of the melting vessel 10 of the SCM apparatus100 depicted in FIG. 1 include water-cooling elements, along withassociated conduits and controllers (not shown), for cooling the wallsand floor of the vessel 10 during operation of the SCM apparatus 100.Other liquid cooling media, besides water, can be employed in thecooling elements of the walls 12 and floor 14 as understood by thoseskilled in the field. Further, the walls 12 and floor 14 can befabricated from various metals and metal alloys that provide sufficientstructural integrity for the vessel 10, and also can be fabricated toaccommodate the cooling elements. As also shown in FIG. 1, the walls 12and floor 14 also include a liner 15 that is generally in contact withthe melted batch 20. In some embodiments, the liner 15 is fabricatedfrom a conventional refractory material that includes one or more ofsilica, zirconia, alumina, platinum and platinum alloys. Liner 15 canalso be fabricated from other conventional refractory materials suitablefor melting glass and glass-ceramic compositions.

Collectively, the walls 12, floor 14 and liner 15 of the melting vessel10 employed by the SCM apparatus 100 allow for the formation of a skulllayer 20 a between the melted batch 20 and the liner 15. In particular,the walls 12 and floor 14 of the vessel 10 are cooled by thewater-cooling elements such that the melted batch 20 is cooled below itsmelting point in proximity to the liner 15. As such, the skull layer 20a is a solid, skin of the melted batch 20, serving as a protectivebarrier between the melted batch 20 having a substantially reactiveglass or glass-ceramic composition and the liner 15, which is fabricatedfrom a conventional refractory material. In certain aspects, the skulllayer 20 a developed in the SCM apparatus 100 can range in thicknessfrom about 0.1 to about 5 inches in thickness, e.g., about 0.5 inches, 1inch, 1.5 inches, 2 inches, 2.5 inches, 3 inches, 3.5 inches, 4 inches,4.5 inches, 5 inches and all thickness values between these amounts.

Referring again to FIG. 1, the melting vessel 10 is depicted inexemplary form with a port 30 in one of the walls 12 for conveying abatch of raw materials 34 below the glass line 22 of the melted batch20. In other embodiments (not shown), the port 30 is situated above theglass line 22. In other aspects consistent with the depiction in FIG. 1,the port 30 is situated at a location about 1 to 20 inches below theglass line 22. Preferably, the port 30 is situated at a location about 2to 10 inches below the glass line 22. The batch of raw materials 34includes the constituents for the glass or glass-ceramic composition ofthe melted batch 20. As shown in FIG. 1, the port 30 includes an auger32 for moving the raw materials 34 into the melted batch 20. Port 30 caninclude various mechanical or electro-mechanical features or elements todrive the raw materials 34 into the melted batch 20. Advantageously, theforced delivery of the raw materials 34 into the melted batch 20 belowthe glass line 22 (e.g., by an auger 32) ensures that the raw materials34 are mixed and melted within the melted batch 20 without directexposure to the liner 15 above the glass line 22 in a melted form. Belowthe glass line 22, the liner 15 is protected by a skull layer 20 aformed directly from the melted batch 20 itself within the vessel 10. Assuch, the arrangement of the SCM apparatus 100 with a port 30 thatdelivers a batch of raw materials 34 below the glass line 22 eliminates,or at a minimum, significantly reduces degradation to the liner 15 ofthe vessel 10. For those embodiments of the vessel 10 with a port 30above the glass line 22, the port 30 can be configured to minimizeexposure of the raw materials 34 to the liner 15 above the glass line 22by ensuring that the raw materials 34 are displaced from liner 15 asthey are forced into the vessel 10 and into the melted batch 20.

As also depicted in FIG. 1 in exemplary form, the SCM apparatus 100includes a single burner 40 within the floor 14 of the melting vessel10. Other configurations of the SCM apparatus 100 can employ multipleburners within the floor 14 of the vessel 10, depending on the size ofthe vessel 10 and space available for one or more delivery orificeassemblies 300. The burner 40 is configured to direct a flame 42 withsufficient energy into a batch of raw materials 34 in the vessel 10 toform a melted batch 20. Similarly, the burner 40 continues to provide aflame 42 into the melted batch 20 as additional batches of raw materials34 are fed into the melted batch 20 through the port 30. Othercomponents (not shown) for controlling the burner 40 and flame 42 areconfigured within or coupled to the SCM apparatus 100 as understood bythose skilled in the field. The configuration of the burner 40 such thatit can directly provide a flame 42 directly into the melted batch 20affords the SCM apparatus 100 with advantages over other conventionalmelting apparatus. The direct exposure of the melted batch 20 to a flame42 from the burner 40 ensures that maximum input energy is delivereddirectly to the raw materials 34 to form the melted batch 20 at a highefficiency. Further, the direct exposure of the melted batch 20 to theflame 42 ensures that the melted batch 20 is mixed and agitated to avoidsegregation and ensure a high degree of homogeneity in the melted batch20. Still further, the direct exposure of the melted batch 20 to theflame 42 allows for oxidation or reduction of the metal(s) in the batchof raw materials 34 and the melted batch 20 as desired, depending on thefuel-to-oxygen ratios employed by the burner 40 in producing the flame42.

Referring again to FIG. 1, the SCM apparatus 100 also includes adelivery orifice assembly 300 in the floor 14 of the melting vessel 10.The delivery orifice assembly 300 is configured to deliver the meltedbatch 20 from the vessel 10 into a containment vessel 50. In certainembodiments, the delivery orifice assembly 300 is heated for thecontrolled delivery of the melted batch 20 into the containment vessel50. Various heating and cooling arrangements can be employed with thedelivery orifice assembly 300 to control the viscosity of the meltedbatch 20 such that it flows at a controlled rate into the containmentvessel 50 including but not limited to induction, resistive winding,burner with air purge, and direct fired metal with adaptive cooling.More particularly, the location and configuration of the deliveryorifice assembly 300 in the floor 14 in proximity to the burner 40 ofthe vessel 10 allows the SCM apparatus 100 to maintain a sufficientlycontinuous skull layer 20 a to protect the liner 15 from degradationfrom the melted batch 20 while also ensuring that the assembly 300penetrates the water-cooled floor 14 such that a skull layer 20 a doesnot form over it. The delivery orifice assembly 300 can then deliver themelted batch 20 to a containment vessel 50 through a localized reductionin viscosity of the melted batch 20 in close proximity to the assembly300. By situating the delivery orifice assembly 300 in the floor 14(rather than in a wall 12, for example), gravity can be used to assistin the flow of the melted batch 20 into the containment vessel 50. Incontrast, situating a delivery orifice assembly in a wall of the SCMapparatus is not preferred as doing so would significantly increase thelikelihood of a skull layer forming over the orifice of the assembly.Further engineering adjustments would be necessary to ensure flow of themelted batch, such as adding an extension of the inner liner (e.g.,inner liner 320 as shown in FIG. 3A) of the delivery orifice assemblyinto the melting vessel 10. Yet this extension of the inner liner wouldbe exposed to the substantially reactive melted batch and thereforedegrade in a short period of time. Consequently, the delivery orificeassembly 300 should be located in the floor 14 in proximity to theburner 40 to optimize functionality. As a result, the degree of localviscosity reductions in the melted batch 20 (i.e., through heating bythe delivery orifice assembly 300) necessary for flow of the meltedbatch are reduced, which aids in the preservation of the skull layer 20a. Further, by situating the delivery orifice assembly 300 in the floor14 in relative proximity to the burner 40 and flame 42, the deliveryorifice assembly 300 can take advantage of the localized heat from theflame 42 and its penetration through the water-cooled floor 14 topromote or arrest flow of the melted batch 20 into the containmentvessel 50 while preserving the integrity of the skull layer 20 a in theremainder of the vessel 50.

Still referring to FIG. 1, the containment vessel 50 of the SCMapparatus 100 can take on a variety of forms for batch runs or periodicruns. For example, vessel 50 can be a mold with graphite walls forreceiving the melted batch 20 and molding it into a desired shape, e.g.,a plate. Vessel 50 can also be a containment apparatus for holding watersuch that melted batch 20 is delivered directly into the water withinthe vessel 50 (e.g., as shown schematically in FIG. 1). The containmentvessel 50 can also be an apparatus that includes water-cooled rollersfor receiving the melted batch 20 and rolling it into a desired shape,e.g., a continuous plate, prior to being sectioned by a downstreamcutting apparatus (not shown).

Referring now to FIG. 1A, a cross-sectional, optical micrograph of awall 12 of the melting vessel 10 of an SCM apparatus 100 is depictedafter the completion of a periodic or batch run employed to form amelted batch 20 of a phase-separable, copper-containing antimicrobialglass composition. As shown in FIG. 1A, the wall 12 includes a liner 15fabricated from alumina, a conventional refractory material. Further,FIG. 1A shows that a skull layer 20 a of the phase-separable,copper-containing antimicrobial glass composition has formed over theliner 15, thus protecting it from substantial degradation from thecopper-containing antimicrobial glass composition. More particularly, aninitial melted batch 20 must first be formed in the vessel 10 of the SCMapparatus 100 to form the skull layer 20 a. Hence, some limiteddegradation to the liner 15 can occur during the initial formation ofthe skull layer 20 a. But after the skull layer 20 a has been formed, itwill provide resistance to further degradation of the liner 15 duringcontinued operation of the SCM apparatus 100.

In some aspects, the skull layer 20 a shown in FIGS. 1 and 1A can bemechanically removed from the vessel 10 prior to subsequent use of theSCM apparatus 100 or a rebuild of the apparatus. Such an approach may bewarranted if the SCM apparatus 100 is used to melt various glass andglass-ceramic compositions over time. In other aspects, the skull layer20 a is left on the liner 15 of the vessel 10 before and after repeateduse of the SCM apparatus 100.

Referring to FIG. 2, a method 200 of melting glass and glass-ceramics,particularly glass and glass-ceramic compositions that are substantiallyreactive to conventional refractory materials, e.g., as including one ormore of silica, zirconia, alumina, platinum and platinum alloys, isprovided. The method 200 includes a conveying step 220 for conveying abatch of raw materials (e.g., raw materials 34 shown in FIG. 1) into anSCM apparatus 100 via a port 30 below a glass line 22 of a melted batch20. As noted earlier, the delivery of raw materials below the glass line22 of the melted batch 20 provides advantages, including additionalmixing of the raw materials and protection of the skull layer developedin the SCM apparatus 100 during the method 200. In some implementations,however, the conveying step 220 is conducted such that a batch of rawmaterials is conveyed into the SCM apparatus above the glass line 22,e.g., with an SCM apparatus configuration in which the port 30 issituated above the glass line 22 of the melted batch 20. In otheraspects, the conveying step is conducted such that the batch of rawmaterials is forced into the melted batch 20 through the port 30 bymechanical or electro-mechanical means including but not limited to anauger apparatus.

The method 200 of melting glass and glass-ceramics depicted in FIG. 2optionally includes a preparing step 210 of preparing the batch of rawmaterials for conveyance into the SCM apparatus 100 in step 220. Thepreparing step 210, in particular, can include weighing and mixing theraw materials for the intended glass or glass-ceramic composition of themelted batch 20. For certain particularly reactive compositions, such asphase-separable, copper-containing antimicrobial glass, the rawmaterials can be isolated to avoid cross-contamination with rawmaterials from other glass and glass-ceramic compositions or other glassand glass-ceramic compositions in final or near-final form. Further, thepreparing step 210 can further include transporting the raw materials tothe SCM apparatus 100 by sacks, vessels or other containers suitable forthis function, as understood by those with ordinary skill in the fieldof this disclosure.

Referring again to FIG. 2, the method 200 of melting glass andglass-ceramics includes a directing step 230 for directing a flame(e.g., flame 42 depicted in FIG. 1) from a burner 40 of the SCMapparatus 100 into the batch of raw materials and the melted batch 20with sufficient energy to form the raw materials into the melted batch20. As noted earlier, the direct exposure of the melted batch 20 to aflame from the burner 40 ensures that maximum input energy is delivereddirectly to the raw materials 34 (see FIG. 1) to form the raw materialsinto the melted batch 20 at a high efficiency. Further, the directexposure of the melted batch 20 to the flame ensures that the meltedbatch 20 is mixed and agitated to avoid segregation and ensure a highdegree of homogeneity in the melted batch 20. Still further, the directexposure of the melted batch 20 to the flame allows for oxidation orreduction of the metal(s) in the batch of raw materials 34 and themelted batch 20 as desired, depending on the fuel-to-oxygen ratiosemployed by the burner 40 in producing the flame.

In certain aspects of the method 200, the directing step 230 fordirecting a flame into the batch of raw materials and the melted batch20 can be conducted with sufficient energy to agitate the melted batch20 such that the melted batch in the containment vessel (e.g., vessel 50depicted in FIG. 1) is substantially homogeneous. The directing step 230can also be conducted according to a ratio of oxygen to fuel that is setbased at least in part on an oxidation state of at least one metal(e.g., copper) in the glass or glass-ceramic composition of the meltedbatch 20. Further, the fuel employed in the directing step 230 ofdirecting a flame into the batch of raw materials and the melted batch20 can be natural gas, and the ratio of oxygen to natural gas can be setfrom about 2:1 to about 3:1. In other aspects, the directing step 230 ofdirecting a flame (e.g., flame 42 as shown in FIG. 1) into the batch ofraw materials and the melted batch 20 can include other combustion gasessuch as hydrogen and propane, along with other inert gases such as argonand nitrogen.

According to a preferred aspect of the method 200 of melting glass andglass-ceramics, the conveying and directing steps 220 and 230 areconducted such that the melted batch 20 includes a skull layer 20 a (seeFIGS. 1 and 1A) in contact with the walls 12 and floor 14 of the meltingvessel 10 of the SCM apparatus 100. In particular, the walls 12 andfloor 14 of the vessel 10 can be cooled by water-cooling elements inproximity to the walls and floor during the conveying and directingsteps 220 and 230 such that the melted batch 20 is cooled below itsmelting point in contact with or in close proximity to a refractoryliner (e.g., liner 15 as depicted in FIG. 1) over the walls 12 and floor14 of the melting vessel 10. As such, the skull layer 20 a can be formedduring the conveying and directing steps 220 and 230 as a solid, skin ofthe melted batch 20. Further, an initial skull layer (or a portion ofthe skull layer 20 a) can be initially formed upon an initial melt ofthe raw materials 34 in the vessel 50 in forming the melted batch 20prior to the conveying and directing steps 220 and 230 of the method200. The skull layer 20 a serves as a protective barrier between themelted batch 20, which has a substantially reactive glass orglass-ceramic composition, and the liner 15, which is fabricated from aconventional refractory material. In certain aspects, the skull layer 20a developed according to the method 200 can range in thickness fromabout 0.1 to about 5 inches in thickness, e.g., about 0.5 inches, 1inch, 1.5 inches, 2 inches, 2.5 inches, 3 inches, 3.5 inches, 4 inches,4.5 inches, 5 inches and all thickness values between these amounts.

The method 200 of melting glass and glass-ceramics shown in FIG. 2 alsoincludes a heating step 240 for heating a delivery orifice assembly 300located at the bottom or floor of the SCM apparatus 100 to convey themelted batch 200 through the orifice assembly into a containment vessel50. Various heating and cooling arrangements can be employed in theheating step 240 to control the viscosity of the melted batch 20 inproximity to the delivery orifice assembly 300 such that it flows at acontrolled rate into the containment vessel 50. These heatingarrangements include but are not limited to induction, resistivewinding, burner, and direct fired (e.g., by transmitting a currentthrough a resistive metal such as platinum). Further, in some aspects,the heating step 240 can be conducted to convey the melted batch 20through the delivery orifice assembly 300 into cooling media 52 (e.g.,water) within the containment vessel 50.

As noted earlier, the provision of conveying the melted batch 20 throughthe delivery orifice assembly 300 in the floor 14 of the vessel 10allows the method 200 to employ the SCM apparatus 100 to maintain asufficiently continuous skull layer 20 a to protect the refractory linerand furnace components of the SCM apparatus 100 from degradation fromthe melted batch 20 while balancing the need to deliver the melted batch20 to a containment vessel 50 through a localized reduction in viscosityof the melted batch 20 in proximity to the delivery orifice assembly300. In certain aspects of the method 200, the heating step 240 forheating a delivery orifice assembly 300 is conducted with an inductionheating process. In another implementation of the method 200, thedelivery orifice assembly 300 employed in the heating step 240 is linedwith a tin oxide liner element.

As also depicted in FIG. 2, the method 200 of melting glass andglass-ceramics can include an optional rolling step 250 when the method200 is conducted in a continuous fashion. For example, melted batch 20can be subjected to the rolling step 250 by conveying the melted batch20 through water-cooled rollers (not shown) and rolling it into adesired shape, e.g., a continuous plate, prior to being sectioned by adownstream cutting apparatus (not shown). Further, an optionalprocessing step 260 can be conducted according to the method 200 to dryand then size the rolled melted batch 20 into final or near-final forms.

In an additional aspect of the method 200 of melting glass andglass-ceramics, the conveying, directing and/or heating steps 220-240are further controlled such that the melted batch 20 is continuouslyconveyed into the containment vessel 50 (e.g., as a continuous plate orsheet). In another aspect of the method 200 of melting glass andglass-ceramics, the conveying, directing and/or heating steps 220-240are further controlled such that the melted batch 20 is periodicallyconveyed into the containment vessel 50 (e.g., in batches). As notedearlier, the containment vessel 50 employed in the method 200 can takeon a variety of forms, depending on the arrangement of the SCM apparatus100 for batch runs or periodic runs.

In certain aspects of the method 200 of melting glass andglass-ceramics, the glass and glass-ceramic compositions of the meltedbatch 20 are substantially reactive to conventional refractorymaterials, e.g., as including one or more of silica, zirconia, alumina,platinum and platinum alloys. For example, the method 200 can beemployed to form a melted batch 20 in which the glass or glass-ceramiccomposition includes a copper-containing oxide. In a preferred aspect,the method 200 is employed to form a melted batch 20 in which the glassor glass-ceramic composition is an antimicrobial glass compositioncomprising a copper-containing oxide in the range from about 10 to about50 mol %. Further, the directing step 230 for directing a flame can beconducted according to a ratio of oxygen to fuel that is set based atleast in part on an oxidation state of the copper in the antimicrobialglass composition.

Referring now to FIGS. 3A-3C, a delivery orifice assembly 300 forconveying a melted batch from an SCM apparatus having a glass orglass-ceramic composition is depicted according to an aspect of thedisclosure. In certain aspects, the glass or glass-ceramic compositionis substantially reactive to a refractory material that includes one ormore of silica, zirconia, alumina, platinum and platinum alloys. Thedelivery orifice assembly 300 includes a susceptor sleeve 310 comprisinga sleeve end 312 for coupling to an SCM apparatus (e.g., the floor 14 ofan SCM apparatus 100 as shown in FIG. 1). In some embodiments, thesusceptor sleeve 310 can be fabricated from a steel, a precious metal, aprecious metal alloy, a metal alloy, and other high temperatureresistant materials suitable for use as a susceptor in an inductionheating arrangement.

Referring again to FIGS. 3A-3C, the susceptor sleeve 310 can, in someaspects, have an internal diameter that ranges from about 0.5 to 4inches, a wall thickness from about 0.02 to 0.50 inches and a heightthat ranges from about 0.5 to 20 inches. For example, the internaldiameter of the susceptor sleeve 310 can be 0.5 inches, 0.6 inches, 0.7inches, 0.8 inches, 0.9 inches, 1 inch, 1.5 inches, 2 inches, 2.5inches, 3 inches, 3.5 inches, 4 inches, and all diameters in betweenthese values. With regard to the wall thickness of the susceptor sleeve310, for example, it can be 0.02 inches, 0.04 inches, 0.06 inches, 0.08inches, 0.1 inches, 0.2 inches, 0.3 inches, 0.4 inches, 0.5 inches, andall thickness values between these values. The height of the susceptorsleeve 310, for example, can be 0.5 inches, 1 inch, 2 inches, 3 inches,4 inches, 5 inches, 6 inches, 7 inches, 8 inches, 9 inches, 10 inches,12 inches, 14 inches, 16 inches, 18 inches, 20 inches, and all heightvalues between these values. In a preferred aspect, the susceptor sleeve310 has an internal diameter from about 0.5 to 1.5 inches, a thicknessfrom about 0.05 to about 0.15 inches and a height of about 1 to 2.5inches. In another preferred aspect, the susceptor sleeve 310 isfabricated from platinum and the wall thickness can be set from about0.025 to 0.05 inches to balance structural rigidity with increasedinduction heating response time. That is, a thinner wall thickness forthe platinum susceptor sleeve 310 can improve induction heating responsetime, but at least some thickness is necessary to preserve mechanicalintegrity of the sleeve within the SCM apparatus 100.

The delivery orifice assembly 300, as shown in FIGS. 3A-3C, alsoincludes a coil 340 that surrounds the susceptor sleeve 310. The coil340 is configured as both an inductor and as a liquid coolantconveyance. In certain aspects, copper tubing (e.g., ⅜″ copper tubing)is employed for the coil 340. More particularly, the coil 340 can becoupled to a buss bar 362 that connects to an induction heatingcontroller 360 (e.g., an Ambrell® Easyheat 10 kW heat station) toperform its induction heating function by generating an oscillatingmagnetic field within the interior of the coil 340 resulting in eddycurrents in the susceptor sleeve 310. Similarly, the coil 340 can becoupled to a cooling controller 370 to perform its cooling function. Thecoil 340 can also include one or more windings 342 (see FIG. 3C). In apreferred aspect, the coil 340 and three windings 342 are joined withthe susceptor sleeve 310 with a refractory cement 350 (see FIG. 3C) suchthat the coil 340 is not in direct physical contact with the susceptorsleeve 310. As such, the refractory cement 350 must be substantiallyelectrically insulative to ensure that there is no electrical couplingbetween the coil 340 and the susceptor sleeve 310. The susceptor sleeve310, as depicted in FIGS. 3A-3C, may also contain a flange 316 toprovide further support for the coil 340.

As also shown in FIGS. 3A-3C, the delivery orifice assembly 300 includesan inner liner 320 configured within the susceptor sleeve 310. The innerliner 320 will be in contact with the melted batch 20 and, as such,should have a refractory composition. More particularly, the inner liner320 is configured to convey a melted batch 20 from the SCM apparatus.The inner liner 320 also includes a liner end 322 that is in proximityto, or in contact with, the sleeve end 312 of the susceptor sleeve 310.In a preferred aspect, the susceptor sleeve 310 also includes an innerflange 314, configured such that the inner liner 320 can rest on theinner flange 314.

Referring again to FIGS. 3A-3C, the delivery orifice assembly 300 alsoincludes a top cap 330 that is positioned over the susceptor sleeve end312 and the liner end 322. The top cap 330 will also be in contact withthe melted batch 20 and, as such, should have a refractory composition.The top cap 330 is also configured with an orifice 334 that issubstantially coincident with the liner end 322 of the inner liner 320.

In some embodiments, the refractory composition of the inner liner 320and top cap 330 includes one or more of quartz, tin oxide, chrome oxide,alumina, fused zirconia, zirconia, zirconia-silica, and combinations ofthese refractories. In a preferred embodiment, the inner liner 320 andthe top cap 330 are fabricated from a composition that includes tinoxide.

As such, the induction heating and cooling controllers 360, 370 can becoupled to the coil 340 to inductively heat the susceptor sleeve 310 tocontrol flow of a melted batch 20 through the orifice 334 and the innerliner 320. In particular, the heating controller 360 generates anoscillating magnetic field within the coil 340 which induces eddycurrents in the susceptor sleeve 310 to heat it. Induction heating andcooling controllers 360, 370 can be located independent or within thesame housing or structure.

Referring again to FIGS. 3A-3C, the delivery orifice assembly 300 can beoperated within an SCM apparatus to control the flow of a melted batchof a glass or glass-ceramic composition, particularly a composition thatis substantially reactive to conventional refractory materials. Forexample, the method 200 (see FIG. 2) for melting such glass andglass-ceramics described earlier can be employed to form a melted batch20 (see FIG. 1) in the melting vessel 10 of an SCM apparatus 100. Duringthe steps of the method 200 required to form the melted batch 20, acooling controller 370 of the delivery orifice assembly 300 can beconfigured to maintain flow of coolant through the coil 340 to ensurethat the local viscosity of the melted batch 20 in proximity to theorifice 334 is high enough to prevent flow of the melted batch throughthe orifice.

In certain aspects, the induction heating controller 360 can be set suchthat the coil 340 is not inductively heated during the formation of themelted batch 20. Upon the development of a melted batch 20 withsufficient volume, the induction heating controller 360 can be adjustedto add power to the system, thereby heating up the susceptor sleeve 310.Heat will then be conducted from the susceptor sleeve 310 to the innerliner 320 and into the melted batch 20. Once the inner liner 320 reachesa temperature sufficient to reduce the viscosity of the melted batch 20in proximity to the orifice 334 such that flow of the melted batchthrough the orifice is obtained, the induction heating controller 360can adjust power to the coil 340 downward to achieve stable flow of themelted batch 20 through the orifice 334. At the same time, coolant flowcan be maintained through the coil 340 by the controller 360 to ensurethat a skull layer within the SCM apparatus remains intact, affordingprotection to the furnace lining and components that would otherwise bein direct contact with the melted batch 20. In addition, the flow rates,and control over the flow rates, of the melted batch 20 through theorifice 334 and the inner liner 320 ensures that the melted batch 20 incontact with the inner liner 320 does not significantly degrade orotherwise corrode it.

Still referring to FIGS. 3A-3C, the delivery orifice assembly 300 canalso maintain or otherwise control temperature of the melted batch 20flowing through its orifice 334 in a further implementation. Inparticular, the induction heating controller 360 can maintaintemperature of the melted batch 20 by two means—automatic and manual. Inautomatic control, a set point is selected by a user, such astemperature, and the power from the controller 360 adjusts up and downto maintain this temperature. As the melted batch 20 flows through theorifice 334, the melted batch itself will be supplying heat so thecontroller 360 may reduce power “downward.” Yet stable flow of themelted batch 20 through the orifice 334 will frequently result in upwardand downward fluctuations in the power from the induction heatingcontroller 360. Conversely, in manual control, a specific power outputis selected for the controller 360 and the controller 360 remains atthis output independent of the temperature measured in the melted batch20. In addition, the water cooling of the coil 340 via controller 370 isused to adjust flow of the melted batch 20 by increasing or decreasingviscosity of the melted batch running through the inner liner 320, or itcan help to create a skull layer 20 a within the inner liner 320. Notethat the cooling aspect of the orifice assembly 300 does not ensure thatthe skull layer 20 a in the SCM apparatus 100 remains intact because, asnoted earlier, the close proximity of the assembly 300 to the burner 40ensures that there is no skull layer above the orifice 334.

The delivery orifice assembly 300 depicted in exemplary fashion in FIGS.3A-3C offers substantial advantages. In particular, the assembly 300offers the ability to rapidly heat and cool the inner liner 320 byinduction with minimal response times. This level of control ensures thefast, robust and constant delivery of the melted batch 20 having a glassor glass-ceramic composition from the SCM apparatus. Another keyadvantage of the delivery orifice assembly 300 is that it can preserveprotection of the furnace linings and components in the SCM apparatus incontact with the reactive glass or glass-ceramic composition of themelted batch 20. In particular, the ability of the delivery orificeassembly 300 to simultaneously cool the coil 340, while it is beingemployed to inductively heat the melted batch 20 in proximity to theorifice 334, ensures that the skull layer in proximity to the orificeassembly 300 (e.g., in the walls 12 and the floor 14) is maintainedduring flow of the melted batch 20 out of the orifice assembly 300.

Other SCM apparatus and delivery orifice assemblies can be configured inview of the aspects of the disclosure. As shown in FIG. 4, for example,an SCM apparatus 400 can be configured with multiple burners 440 anddelivery orifice assemblies 300 spaced at various locations, typicallywithin the floor 414 of the apparatus. The SCM apparatus 400 alsoincludes liquid-cooled walls 412 and a floor 414. By positioningmultiple burners 440 within the floor 414, the SCM apparatus 400 can beemployed to form a melted batch of a glass or glass-ceramic composition,preferably a composition that is substantially reactive to conventionalrefractory materials, with a high degree of homogeneity. In particular,the multiple burners 440 facilitate more uniform agitation of the meltedbatch, viscosity uniformity and more uniform oxidation or reduction ofthe metal constituents within the melted batch.

Further, multiple delivery orifice assemblies 300 can be employed in theSCM apparatus 400 depicted in FIG. 4 to maintain high levels ofmanufacturing throughput to deliver the melted batch at particularmelted batch flow rates, while minimizing the need to excessively reducethe viscosity of the melted batch in proximity to each orifice assembly300. That is, the use of numerous orifice assemblies 300 compared to asingle orifice assembly 300 allows for decreased flow rates through eachorifice while achieving the same manufacturing throughput. As a result,the lower flow rates of the melted batch through each of the orificeassemblies 300 can be translated into relatively higher viscosity levelsof the melted batch in proximity to each orifice assembly 300. Thesehigher viscosity levels of the melted batch 20 (i.e., as manifested inlower local melted batch temperatures) result in less interference withthe solid, skull layer, which plays a role in preserving the furnacelinings and components of the SCM apparatus 400 that would otherwise bein direct contact with the melted batch.

Still further, the SCM apparatus 400 depicted in FIG. 4 also can benefitfrom being configured with multiple ports 430 configured to deliver orotherwise forcefully introduce a batch of raw materials into the meltedbatch within the apparatus. In particular, multiple ports 430 allow forbetter control and uniform delivery of the batch of raw materials intothe melted batch. An SCM apparatus, such as apparatus 400, with multipleports 430 can also be configured for higher manufacturing throughputgiven that larger quantities of batches of raw materials can bedelivered into the melted batch by multiple ports 430.

Aspect (1) of this disclosure pertains to a method of melting glass andglass-ceramics, comprising: conveying a batch of raw materials into asubmerged combustion melting apparatus, the melting apparatus havingliquid-cooled walls and a floor; directing a flame into the batch of rawmaterials with sufficient energy to form the raw materials into a meltedbatch; and heating a delivery orifice assembly within the floor of thesubmerged melting apparatus to convey the melted batch through theorifice assembly.

Aspect (2) of this disclosure pertains to the method of Aspect (1),wherein the melted batch comprises a glass or glass-ceramic compositionthat is substantially reactive to a refractory material, the refractorymaterial comprising one or more of silica, zirconia, alumina, platinum,and platinum alloys.

Aspect (3) of this disclosure pertains to the method of Aspect (1),wherein the melted batch comprises a glass or glass-ceramic compositioncomprising silica and copper oxide.

Aspect (4) of this disclosure pertains to the method of any one ofAspects (1) through (3), wherein the melted batch comprises a skulllayer in contact with the walls and the floor of the submergedcombustion melting apparatus.

Aspect (5) of this disclosure pertains to the method of Aspect (4),wherein the conveying, directing and heating steps are furthercontrolled such that the melted batch is continuously conveyed into thecontainment vessel.

Aspect (6) of this disclosure pertains to the method of Aspect (4),wherein the conveying step is further conducted such that the batch ofraw materials is conveyed below a glass line of the melted batch.

Aspect (7) of this disclosure pertains to the method of any one ofAspects (1) through (6), wherein the step of directing a flame into thebatch of raw materials and the melted batch is further conducted withsufficient energy to agitate the melted batch such that the melted batchin the containment vessel is characterized by substantial homogeneity.

Aspect (8) of this disclosure pertains to the method of any one ofAspects (1) through (7), wherein the glass or glass-ceramic compositioncomprises a copper-containing oxide.

Aspect (9) of this disclosure pertains to the method of Aspect (8),wherein the glass or glass-ceramic composition is an antimicrobial glasscomposition comprising a copper-containing oxide in the range from about10 to about 50 mol %.

Aspect (10) of this disclosure pertains to the method of any one ofAspects (1) through (9), wherein the step of directing a flame isconducted according to a ratio of oxygen to fuel that is set based atleast in part on an oxidation state of at least one metal in the glassor glass-ceramic composition.

Aspect (11) of this disclosure pertains to the method of Aspect (9),wherein the step of directing a flame is conducted according to a ratioof oxygen to fuel that is set based at least in part on an oxidationstate of the copper in the antimicrobial glass composition.

Aspect (12) of this disclosure pertains to the method of Aspect (11),wherein the fuel is natural gas and the ratio is about 2:1 to about 3:1oxygen gas to natural gas.

Aspect (13) of this disclosure pertains to the method of Aspect (12),wherein the step of heating a delivery orifice assembly is conductedwith an induction heating process.

Aspect (14) of this disclosure pertains to the method of Aspect (13),wherein the delivery orifice assembly is lined with a tin oxide linerelement.

Aspect (15) of this disclosure pertains to the a delivery orificeassembly for a submerged combustion melting apparatus, comprising: asusceptor sleeve comprising a sleeve end for coupling to a submergedmelting apparatus; a coil surrounding the susceptor sleeve that isconfigured as an inductor and a liquid coolant conveyance; an innerliner having a first refractory composition disposed within the sleeve,the liner further configured to convey a melted batch from the meltingapparatus and comprising a liner end in proximity to, or in contactwith, the sleeve end; a top cap positioned over the sleeve end and theliner end, the cap having the first refractory composition andconfigured for contact with the melted batch in the melting apparatus,and the cap further comprising an orifice substantially coincident withthe liner end; and an induction heating controller coupled to the coilfor inductively heating the susceptor to control flow of the meltedbatch through the orifice and the inner liner.

Aspect (16) of this disclosure pertains to the delivery orifice assemblyof Aspect (15), wherein the melted batch has a glass or glass-ceramiccomposition.

Aspect (17) of this disclosure pertains to the delivery orifice assemblyof Aspect (16), wherein the glass or glass-ceramic composition issubstantially reactive to a refractory material, the refractory materialcomprising one or more of silica, zirconia, alumina, platinum andplatinum alloys.

Aspect (18) of this disclosure pertains to the delivery orifice assemblyof Aspect (16), wherein the melted batch comprises a glass orglass-ceramic composition comprising silica and copper oxide.

Aspect (19) of this disclosure pertains to the delivery orifice assemblyof Aspect (17), wherein the first refractory composition is selectedfrom refractories consisting of quartz, tin oxide, chrome oxide,alumina, fused zirconia, zirconia, zirconia-silica, and combinations ofthese refractories.

Aspect (20) of this disclosure pertains to the delivery orifice assemblyof any one of Aspects (15) through (19), wherein the first refractorycomposition comprises tin oxide.

Aspect (21) of this disclosure pertains to the delivery orifice assemblyof any one of Aspects (15) through (20), wherein the susceptor sleevehas a composition selected from the group consisting of a steel, aprecious metal and a precious metal alloy.

Aspect (22) of this disclosure pertains to the delivery orifice assemblyof Aspect (21), wherein the susceptor sleeve further comprises an innerflange, and further wherein the inner liner rests on the inner flange.

Aspect (23) of this disclosure pertains to the delivery orifice assemblyof Aspect (22), wherein the coil is joined in substantial contact withthe susceptor sleeve with a refractory cement.

Aspect (24) of this disclosure pertains to a submerged combustionmelting apparatus, comprising: a melting vessel for preparing a meltedbatch, the vessel comprising a plurality of walls and a floor, eachcomprising a metal alloy and a water-cooling element; a port in one ofthe walls for conveying a batch of raw materials into the melted batch;a burner in the floor for directing a flame into the vessel withsufficient energy to form the melted batch; and a delivery orificeassembly in the floor for delivering the melted batch.

Aspect (25) of this disclosure pertains to the submerged combustionmelting apparatus of Aspect (24), wherein the delivery orifice assemblycomprises: a susceptor sleeve comprising a sleeve end for coupling tothe floor of the melting vessel; a coil surrounding the susceptor thatis configured as an inductor and a liquid coolant conveyance; an innerliner configured within the sleeve having a first refractorycomposition, the liner comprising a liner end in proximity to, orcontact with, the sleeve end and configured to convey the melted batchfrom the melting vessel; a top cap positioned over the sleeve end andthe liner end, the cap having the first refractory composition andconfigured for contact with the melted batch in the melting vessel, andthe cap further comprising an orifice substantially coincident with theliner end; and an induction heating controller coupled to the coil forinductively heating the coil to control flow of the melted batch throughthe orifice and the inner liner into the containment vessel.

Aspect (26) of this disclosure pertains to the submerged combustionmelting apparatus of Aspect (24), wherein the port is located at aposition in one of the walls for conveying the batch of raw materialsbelow a glass line of the melted batch.

Aspect (27) of this disclosure pertains to the submerged combustionmelting apparatus of Aspect (25), wherein the first refractorycomposition is selected from refractories consisting of quartz, tinoxide, chrome oxide, alumina, fused zirconia, zirconia, zirconia-silica,and combinations of these refractories.

Aspect (28) of this disclosure pertains to the submerged combustionmelting apparatus of Aspect (27), wherein the first refractorycomposition comprises tin oxide.

Aspect (29) of this disclosure pertains to the submerged combustionmelting apparatus of Aspect (27), wherein the susceptor sleeve has acomposition selected from the group consisting of a steel, a preciousmetal and a precious metal alloy.

It will be apparent to those skilled in the art that variousmodifications and variations can be made without departing from thespirit or scope of the invention.

What is claimed:
 1. A delivery orifice assembly for a submergedcombustion melting apparatus comprising: a susceptor sleeve comprising asleeve end configured to be coupled to a submerged melting apparatus; acoil surrounding the susceptor sleeve configured as an inductor and aliquid coolant conveyance; an inner liner having a first refractorycomposition disposed within the susceptor sleeve, the inner linerfurther configured to convey a melted batch from the submerged meltingapparatus and comprising a liner end in proximity to, or in contactwith, the sleeve end; a top cap positioned over the sleeve end and theliner end, the top cap having the first refractory composition andconfigured to contact the melted batch in the submerged meltingapparatus, and the top cap further comprising an orifice substantiallycoincident with the liner end; and an induction heating controllercoupled to the coil and configured to inductively heat the susceptorsleeve to control a flow of the melted batch through the orifice and theinner liner.
 2. The delivery orifice assembly of claim 1, wherein themelted batch has a glass or glass-ceramic composition.
 3. The deliveryorifice assembly of claim 2, wherein the glass or glass-ceramiccomposition is substantially reactive to a refractory material, therefractory material comprising one or more of silica, zirconia, alumina,platinum, and platinum alloys.
 4. The method of claim 2, wherein theglass or glass-ceramic composition comprises silica and copper oxide. 5.The delivery orifice assembly of claim 3, wherein the first refractorycomposition is selected from refractories consisting of quartz, tinoxide, chrome oxide, alumina, fused zirconia, zirconia, zirconia-silica,and combinations thereof.
 6. The delivery orifice assembly of claim 1,wherein the first refractory composition comprises tin oxide.
 7. Thedelivery orifice assembly of claim 1, wherein the susceptor sleeve has acomposition selected from a group consisting of a steel, a preciousmetal, and a precious metal alloy.
 8. The delivery orifice assembly ofclaim 7, wherein the susceptor sleeve further comprises an inner flange,and the inner liner rests on the inner flange.
 9. The delivery orificeassembly of claim 8, wherein the coil is joined in substantial contactwith the susceptor sleeve with a refractory cement.
 10. A submergedcombustion melting apparatus, comprising: a melting vessel configured toprepare a melted batch, the melting vessel comprising a plurality ofwalls and a floor, each of the plurality of walls and the floorcomprising a metal alloy and a water-cooling element; a port in one ofthe walls configured to convey a batch of raw materials into the meltedbatch; a burner in the floor configured to direct a flame into themelting vessel with sufficient energy to form the melted batch; and adelivery orifice assembly in the floor configured to deliver the meltedbatch.
 11. The submerged combustion melting apparatus of claim 10,wherein the delivery orifice assembly comprises: a susceptor sleevecomprising a sleeve end configured to be coupled to the floor of themelting vessel; a coil surrounding the susceptor sleeve configured as aninductor and a liquid coolant conveyance; an inner liner configuredwithin the susceptor sleeve having a first refractory composition, theinner liner comprising a liner end in proximity to, or contact with, thesleeve end and configured to convey the melted batch from the meltingvessel; a top cap positioned over the sleeve end and the liner end, thetop cap having the first refractory composition and configured tocontact the melted batch in the melting vessel, and the top cap furthercomprising an orifice substantially coincident with the liner end; andan induction heating controller coupled to the coil configured toinductively heat the coil to control a flow of the melted batch throughthe orifice and the inner liner into a containment vessel.
 12. Thesubmerged combustion melting apparatus of claim 10, wherein the port islocated at a position in one of the walls configured to convey the batchof raw materials below a glass line of the melted batch.
 13. Thesubmerged combustion melting apparatus of claim 11, wherein the firstrefractory composition is selected from refractories consisting ofquartz, tin oxide, chrome oxide, alumina, fused zirconia, zirconia,zirconia-silica, and combinations of these refractories.
 14. Thesubmerged combustion melting apparatus of claim 13, wherein the firstrefractory composition comprises tin oxide.
 15. The submerged combustionmelting apparatus of claim 13, wherein the susceptor sleeve has acomposition selected from a group consisting of a steel, a preciousmetal, and a precious metal alloy.